The most 'efficient' method would be to tap off at a switch to feed power to the next switch. The only reason here being that you'd be able to run 12-2 for the entire circuit (assuming single pole switching only with the example given).
The only true difference in this over running to the light first and creating a switch loop is that you are now required to have a neutral at each switch box - which would then call for 12-3 for the loops.
As well though, this is on the condition of new wiring in presumably new construction - giving you the freedom on locating the wiring. But at the same time, it all comes down to the distance to the fixtures and switches. If you have a light right by the panel and the switch is on the other side of the room, it'd be easier to run the short distance of homerun 12-2 to the light and then a 12-3 loop to the switch rather than the two long distance runs of 12-2. Seeing as 12-2 is nearly half the cost of 12-3 though, you'd be able to essentially run a 2 wire across the room and back for the same as using a single 3 wire. In this case it'd be efficient in only have a single strand of romex between each device, but you'd be paying a little more if you don't have 12-3 on hand - making it less cost efficient.
In short; it depends on the situation based on the locations of everything. Running 12-2 throughout, tapping off to feed other rooms at the switches, is probably the simplest answer to being the most 'efficient'. Simply because you're now required to have access to neutral at each switch.
I'll tack this on for extra measure. Your primary hot coming from the panel, regardless of how the wires are ran physically, must tap off such as this to feed each switch in parallel to one another. The the load on each switch is as well included in parallel powered from that particular switch.